Four more staff at the Áras Attracta care home are under investigation as part of a probe into the alleged abuse of residents.

It brings to at least 18 the number of staff whose conduct is being scrutinised as part of a HSE commissioned investigation into care at the home for people with intellectual disabilities in Swinford, Co Mayo.

The inquiry was sparked last year by the broadcast of footage recorded by an undercover reporter with the RTÉ Investigations Unit on 'Prime Time'.

Sources said the four staff had been identified during the course of a Trust in Care investigation being headed up by Christy Lynch, a disability services expert and chief executive of the KARE disability organisation in Kildare.

The investigation involves analysis of further footage which was never broadcast, the Irish Independent understands.

No decision has been made on whether the four members of staff will be allowed to continue working while the investigation progresses.

Other staff identified during the course of the probe have been taken off duty.

In a statement the HSE said: "As part of the ongoing Trust in Care investigation into Áras Attracta, and following viewing of the 'Prime Time' footage by the investigation team, a number of additional staff will now form part of the Trust in Care investigation. Due process is under way at this stage.

"The HSE wishes to reassure families and residents that plans are in place to ensure that there is no disruption in service to residents."

Six staff members, five women and one man, are facing charges of assault arising out of the secret film.

The HSE is currently restructuring management and staffing arrangements at Áras Attracta.

The Health Information and Quality Authority last week issued the HSE with notice of a proposal to cancel the registration of one of the centres at the care home.